如何使用索引访问 ListView 中的委托属性 [英] How to access delegate properties in ListView using index

问题描述

我想访问 ListView 中的委托属性.我试过 contentItem 但有时它是 undefined.

I want to access delegate properties in ListView. I've tried with contentItem but sometimes it's undefined.

这是我的代码:

ListModel{
            id: modeldata
            ListElement{
                name:"don"
                rank:1
            }
            ListElement{
                name:"shan"
                rank:2
            }
            ListElement{
                name:"james"
                rank:3
            }
            ListElement{
                name:"jeggu"
                rank:4
            }
        }
        Component{
            id: delegateitem
            Row {
                property int count: rank
                Rectangle{
                    width: 100
                    height: 50
                    Text{
                        anchors.centerIn: parent
                        text: name
                    }
                }
            }
        }
        ListView{
            id: listview
            focus: true
            anchors.fill: parent
            model: modeldata
            delegate: delegateitem
            onCurrentIndexChanged: {
        console.log("position",currentIndex)
        console.log("property",contentItem.children[currentIndex].count);
            }
        }

位置 1 处的问题无效输出

qml: position 0
qml: property 1
qml: position 1
qml: property undefined
qml: position 2
qml: property 2
qml: position 3
qml: property 3

推荐答案

首先:如果您尝试从列表外部访问列表元素，这是一个很好的指示，您应该重新考虑您的设计.

First of all: if you are trying to access list elements from outside your list, this is a good indicator that you should rethink your desing.

现在的解决方案是:一个列表视图有更多的孩子，而不仅仅是它的项目.例如，您可以通过定义属性属性字符串类型:myType""来过滤它们.然后通过循环遍历子项来查找项，并且只选取类型属性等于myType"的项.它有点像黑客，但同样，您一开始就不应该这样做.

Now the solution: a listview has more children than only its items. You can filter them out by defining a property "property string type: "myType" " for example. Then find the items by looping over the children and only take those where the type property equals "myType". Its somewhat of a hack but again you should really not be doing this in the first place.

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